Non-Patent Literatures 3 to 6, 10, 12, 13, 15, and 18 describe an ID (Identity)-based encryption (IBE) scheme which constitutes one class of the functional encryption scheme. Non-Patent Literatures 2, 7, 9, 16, 19, 23 to 26, and 28 describe an attribute-based encryption (ABE) scheme which constitutes another class of the functional encryption scheme.